CONCRETE

CONCRETE

1. COMPONENT

   • 1 part cement, 2 parts fine aggregate, 4 parts coarse aggregate, 0.4-0.5 part water

2. hydration

   • too much water--weak
     • too little water--still and unworkable

3. PROCESS

   • concrete is fluid and shapeless before it hardens
   • formwork--temporary support or moulds to hold the liquid concrete
   • IN SITU PRE-CAST
   • PROPS & BRACING--support the formwork during the curing process
   • the formwork is removed once the concrete is harden

4. FINISHES

   • sand-blasted, exposed aggregate, raked finish, bush hammered, board-marked, board & batten

5. REINFORCEMENT

   • strong in compression, weak in tension
     • steel reinforcement--MESH, BARS
       • REINFORCED CONRETE

6. PROPERTIES

   • hardness: high
   • fragility: low
   • ductility: very low
   • flexibility/plasticity: low
   • porosity/permeability: medium-low (proportions & components)
   • density: medium-high
   • conductivity: poor
   • durability/life span: very durable
   • reusability/recyclability: medium-low, can be reused (aggregate)
   • sustainability/carbon footprint: high embodied energy, non-renewable, long lasting
   • cost: effective, labour

7. CONSIDERATION

   • water damage and oxidation of the steel bars--structural degration
   • poor vibration of the concrete